Collaborative Research: Numerical/Experimental Investigation of Solar Chimney Power Plants

In collaboration with H. Fasel, University of Arizona

Funded by NSF

Solar chimney power plants promise to become a viable alternative to existing fossil and solar power plants. For such plants air under a circular collector is heated by the sun light. The hot air rises through a central chimney. The resulting natural convection drives turbines at the foot of the chimney and sucks in air from the perimeter of the collector. Although a prototype was operated successfully in Manzanares, Spain, in the 80s the technology has never been realized on a larger scale.

Proposed 200MW solar chimney power plants by Schlaich & Bergermann Solar

Proposed 200MW solar chimney power plants by Schlaich & Bergermann Solar.

Different from photovoltaic and concentrated solar power plants where the power scales with the collector area, for solar chimney power plants the power scales with the product of collector area and chimney height. Although the conversion efficiency is relatively low, this cubic scaling and the low collector construction cost make large-scale solar chimney plants competitive with fossil fuel plants.

The technology has never been realized on a large scale mainly because of the many remaining uncertainties in particular with respect to the fluid dynamics of the radial collector flow. This lack of physical understanding makes the technology too risky for investing in full-size plants.

While the plane channel flow with convection (Rayleigh-Bénard-Poiseuille flow) has been investigated in great detail and is relatively well understood, the radial Rayleigh-Bénard-Poiseuille flow has attracted close to no attention. Because of its importance for chemical vapor deposition reactors some research was carried out for outward radial flow. However, no flow instability analysis is available for inward radial channel flow with convection.

As part of this research project the flow instabilities governing laminar, transitional, and turbulent inward radial Rayleigh-Bénard-Poiseuille flow are systematically explored. Towards this end, computer simulations are carried out for investigating the primary and secondary instabilities and their role in the evolution and dynamics of flow structures that will have a profound effect on both heat transfer and streamwise pressure drop in the collector.

Instantaneous iso-surfaces of Q=0.01 and 0.1 colored by temperature (blue: 300K, red: 350K) showing collector and chimney inflow.

Instantaneous iso-surfaces of Q=0.01 and 0.1 colored by temperature (blue: 300K, red: 350K) showing collector and chimney inflow.

For the laminar and transitional regime, the simulation strategies are validated by experiments using scientifically instrumented scaled solar chimney models. A 1:30 scale model of the Manzanares plant was designed and constructed. With funding from the Research Corporation for Science Advancement a research partnership with a Catalina High School teacher was established during 2012 & 2013. During the summer of 2013 a student from Tucson High participated in the project. Significant portions of the preliminary design and design analysis were carried out by visiting students from ENSMA (Poitiers, France) and SUPMECA (Paris, France).

1:30 scale model of Manzanares plant on roof of Aerospace and Mechanical Engineering Department at University of Arizona.

1:30 scale model of Manzanares plant on roof of Aerospace and Mechanical Engineering Department at University of Arizona.

May 2016 visit of NMSU team with researchers at University of Arizona

Visit of NMSU researchers with University of Arizona researchers, May 2016, Tucson, AZ.

NMSU and UA researchers discussion details of collector design.

NMSU and UA researchers discuss details of collector design.

  1. Hasan, M.K., and Gross, A., “Numerical Investigation of Radial Flow in Solar Chimney Power Plant Collector,” AIAA-2017-1010, 55th AIAA Aerospace Sciences Meeting, 9-13 January 2017, Grapevine, TX
  2. Fasel, H., Meng, F., and Gross, A., “Numerical and Experimental Investigation of a Solar Chimney Power Plant,” 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Kruger National Park, South Africa, 20-23 July 2015
  3. Fasel, H.F., Meng, F., Shams, E., and Gross, A., “CFD Analysis for Solar Chimney Power Plants,” Solar Energy, Vol. 98, Part A, 2013, pp. 12–22
  4. Meng, F., Gross, A., and Fasel, H.F., “Computational Fluid Dynamics Investigation of Solar Chimney Power Plant,” AIAA-2013-2460, 2013
  5. Fasel, H., Shams, E., and Gross, A., “CFD Analysis for Solar Chimney Power Plants,” HEFAT2012, Malta, 16-18 July 2012
  6. Shams, E. Gross, A., and Fasel, H., “Performance Analysis of Solar Chimneys of Different Physical Scales Using CFD,” ES2011-54537, Proc. 5th ASME International Conference on Energy Sustainability, pp. 2147-2156